Heretofore, many efforts have been made to provide a clinch type nail having multiple prongs which may be driven into a substrate where the penetrating portions of the prongs move toward each other to clinch a portion of the substrate and resist withdrawal. Most of these prior nails have been driven into a relatively soft substrate such as wood or the like as exemplified by the U.S. patents to Tyrzicky, U.S. Pat. No. 2,287,843 and Couch, U.S. Pat. No. 3,292,481.
Other clinch type nails or staples have been provided for driving into a relatively hard dense substrate such as steel or other metal as exemplified by U.S. patent to Catlin, et al., U.S. Pat. No. 2,873,447 and my prior U.S. Pat. Nos. 3,095,777; 3,871,264; 4,003,286; and 4,193,333.
Additionally, the U.S. patent to Ballou discloses a nail having a shank which is generally rectangular in cross-section with a pair of prongs at one end, however, the prongs are bent into engagement with each other before the nail is driven.
Further, some prior art nails such as the U.S. patent to Gair, U.S. Pat. No. 2,366,962 have been provided in which the penetrating end has a pair of spaced portions.